Two specimens of Chlorophthalmus nigromarginatus Kamohara, 1953 (51.02 mm, 66.04 mm in standard length) belonging to the family Chlorophthalmidae were collected on February 8, 2022 in the eastern Jeju-do Island, Korea using a bottom trawl. The species has the following morphological characteristics: snout length almost the same as orbit diameter, bump absent on predorsal, caudal fin with posterior black margin. C. nigromarginatus is morphologically very similar to C. acutifrons but can be distinguished by caudal fin with black margin (C. acutifrons has no black margin). Molecular analyses showed that our specimens almost matched with C. nigromarginatus according to mtDNA 16S rRNA sequences (99.8%). Therefore, we propose a new Korean name for C. nigromarginatus, “Geomeun-kko-ri-pa-rang-nun-mae-tung-i”.